The invention relates to a support arrangement comprising a first support part for connection to a suspension strut and to a steering device of a motor vehicle, and a second support part for holding a wheel bearing, the first support part and the second support part having wall regions formed in a metal-casting process, the first support part and the second support part being connected to each other by means of screws, and two brake support arms being formed on the second support part for attachment of the brake device.
The construction of motor vehicles combines many component parts which are designed for different functions and accordingly have to satisfy different safety regulations. Any saving in weight in the design is welcome, since this enables a saving during operation of the motor vehicle on an amount of fuel which, under some circumstances, far exceeds the amount of primary energy which has to be used to produce the motor vehicle. A saving in weight and in: fuel is also desirable with regard to protection of the environment. The lower the weight of the vehicle, the lower the weight of the vehicle to the road and the simpler the disposal at the end of the vehicle""s working life. However, the saving in weight should not obscure the safety aspects. The individual parts of the motor vehicle have to ensure the greatest possible safety at the least possible weight.
DE 197 42 027 A1 discloses a support arrangement according to the generic type. The support arrangement consists essentially of a first shaped casting which supports the pivot bearing, and of a second shaped casting which holds the wheel bearing for the wheel axle and the wheel flange connected thereto, and has arms for attachment of the brake shoes. The two shaped castings are connected to each other by means of screws. As the two shaped castings are being screwed together, a shoulder projection, which can be deformed plastically, exerts pressure on the end side of the wheel bearing. The first shaped casting, in particular, is made with a relatively large amount of material and having relatively great wall thicknesses, at least in the region between the screw connection and the pivot bearing.
Taking this prior art as the starting point, the object of the invention is to provide a support arrangement for motor vehicles, which arrangement has the greatest possible strength at the smallest possible overall weight, can be produced cost-effectively and allows the use of first generation wheel bearings.
The foregoing object is achieved by providing a support arrangement comprising a first support part for connection to a suspension strut and to a steering device of a motor vehicle, and a second support part for holding a wheel bearing, the first support part and the second support part having wall regions formed in a metal-casting process, the first support part and the second support part being connected to each other by means of screws, and two brake support arms being formed on the second support part for attachment of the brake device, and the one brake support arm having wall regions which are formed such that they are substantially thinner than the corresponding wall regions of the other brake support arm.
It is advantageous for as little material as possible to be used in the casting process for producing the support arrangement. This is achieved by the one brake support arm having wall regions which are formed such that they are at least 20%, preferably at least 40%, thinner than the corresponding wall regions of the other brake support arm. The brake support arms can differ in design corresponding to the load of the brake device. The arm which supports the small brake shoes which act in the forward direction of travel has to be designed for a substantially greater braking force than the arm for the small brake shoes which act in the rearward direction of travel. This is achieved by further wall regions being formed on the first support part for connection to the suspension strut and to the steering device of a motor vehicle, said wall regions being designed such that they are substantially thinner in some areas than the adjacent wall regions of the second support part, the wall regions of the first support part enclosing an angle of xcex1 less than 180xc2x0 with the wall regions of the second support part.
The support arrangement has different wall regions which are formed in a metal-casting process, are arranged adjacent to one another and are designed in such a manner that the support arrangement is able to carry out fairly different functions, for example the connection to the suspension strut and to the steering device of the motor vehicle, the holding of the wheel bearing and the attachment of the brake device.
Because the support arrangement is produced from two support parts which are screwed to each other, in contrast to a support arrangement which is produced from one part four molds instead of two have to be constructed. However, the additional outlay for the construction of the molds and for the screw connection is made up for by obtaining twice the amount of degrees of freedom. Undercuts which are difficult to produce between wall regions which are arranged at an angle to one another and which would require extra mold cores are no longer necessary. At the same time, material and therefore weight can be saved in the region of the undercuts. The location of the sprue can be selected separately for the two support parts and therefore more favorably for the casting and cooling conditions. The mold parting line can also be selected separately for the two support parts and therefore more favorably for their removal from the mold. The separating line between the two support parts can be set in such a manner than an optimum design with regard to safety and saving in weight is possible both for the first support part and for the second support part. Because two individual support parts are produced, an optimum selection of material can be made for each support part corresponding to the stress to which it is subjected. The modular construction enables different component parts to be combined with one another. This combination option gives greater flexibility in production and in storage.